English Reference
noun · adjective · verb

union

n. · adj. · v.
US /ˈjunjən/ UK /jˈuːniən/ union UK spelling union's, union's, unioned

  1. 01 B1 Intermediate

    n.an organisation of workers that protects their rights and helps them talk to their employers.

    n.an organised association of workers formed to protect and further their rights and interests; a trade union.

    Simple

    The workers decided to join the union to ask for better pay.

    In context

    The union representatives met with the board of directors to negotiate a new collective bargaining agreement regarding workplace safety.

    labour uniontrade unionguild
  2. 02 B2 Upper Intermediate

    n.a group of states or countries that have joined together to form one political unit.

    n.a political unit consisting of a number of states or provinces that have joined together for a common purpose.

    Simple

    The European Union allows people to travel easily between member countries.

    In context

    The treaty aimed to create a more perfect union between the neighbouring territories, harmonising their trade laws and border controls.

  3. 03 B2 Upper Intermediate

    n.the act of joining two or more things into one, or the state of being joined.

    n.the action of joining together or the state of being joined into a single entity.

    Simple

    The union of the two companies created the largest tech firm in the city.

    In context

    The architect sought a perfect union of form and function, ensuring the building was as beautiful as it was practical.

  4. 04 B2 Upper Intermediate Formal Law

    n.the state of being married or joined in a relationship.

    n.the state of being joined in marriage or a similar long-term relationship.

    Simple

    Their union was celebrated by friends and family from both countries.

    In context

    The legal union of the two heirs served to consolidate the family estates and end decades of litigation.

  5. 05 B1 Intermediate British English

    n.an organisation at a university that looks after students' social lives and rights.

    n.a student organisation at a university or college providing social facilities and representing student interests.

    Simple

    We went to the student union to grab a cheap lunch between lectures.

    In context

    The student union voted to boycott the new campus catering contract in protest of rising prices.

    student councilguild
  6. 06 C1 Advanced Technical Math

    n.a set that contains all the members of two or more other sets.

    n.the set containing all elements that are members of at least one of a given collection of sets.

    Simple

    The union of set A and set B includes every number found in either group.

    In context

    To solve the probability problem, the students had to calculate the union of two overlapping data sets.

  7. 07 C2 Proficiency Technical Computing

    n.a special way to store data where different types of information share the same memory space.

    n.a data structure that allows multiple variables to share the same memory location, though only one can be used at a time.

    Simple

    The programmer used a union to save memory in the embedded system.

    In context

    Unlike a struct, a union allocates only enough memory for its largest member, which requires careful management of data types.

  8. 08 B2 Upper Intermediate

    adj.describing something that belongs to or is done by a workers' union.

    adj.pertaining to or represented by a labour union.

    Simple

    He is a union member and never misses a monthly meeting.

    In context

    The company faced criticism for hiring non-union contractors to complete the electrical work on the new factory.

    non union
  9. 09 C2 Proficiency Technical Math

    v.to combine two groups of things into one large group in mathematics.

    v.to perform the union operation on two or more mathematical sets.

    Simple

    If you union these two lists, you get a complete list of all customers.

    In context

    The algorithm was designed to union the results of several database queries into a single, deduplicated output.


Etymology 1

(locomotive): Derived from the name of the only U.S. company to use that configuration.

Etymology 2

Probably a variant spelling of Onion.

Etymology 3

Clipping of Oxford Union.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B1 · Intermediate
Frequency Very common
Updated